The invention relates to a packaging dispensing device and method for dispensing stacks of nested trays to a packing apparatus for packing eggs, fruits, or like delicate articles. In the packing of eggs and fruits it is common to use stackable trays or boxes of moulded paper pulp, or plastic material having formed therein rows of pockets. In the case of eggs, such trays for example come in sizes of 5 rows of 6 pockets (also known as flats), and optionally in sizes of 2 or 3 rows of 6 pockets (also known as boxes or cartons). Occasionally other sizes have been used as well.
Packing has been generally done by apparatuses such as those disclosed in U.S. Pat. No. 3,169,354, U.S. Pat. No. 5,096,041, or U.S. Pat. No. 5,365,717. When such machines are combined with handling, grading, sorting, and/or processing systems, such as disclosed in U.S. Pat. No. 3,928,184, U.S. Pat. No. 4,086,998, U.S. Pat. No. 4,383,613, U.S. Pat. No. 4,569,444, or U.S. Pat. No. 6,029,424, the throughput of packing trays is required at such an elevated rate that feeding individual trays to multiple packing apparatuses has also been automated. Egg trays are supplied to the egg grading and packing industry in nested stacks. During packing the egg trays, flats or boxes, are dispensed individually from the nested stacks and are fed to a conveyor for transport through a packing line to be filled with eggs. Usually the packing line can be converted to packing into different sized trays. To feed individual trays, each packing apparatus along a distribution conveyor of a grading system is usually provided with a denesting unit that can feed individual trays from a stack of nested trays. Such nested stacks can have a height of up to 140 trays to allow economical transport between the manufacturing plant of the trays and the packing plant. The material of the trays, whether it is paper pulp or plastic has a tendency to cling together and resist denesting. This tendency of sticking and clinging together can cause frequent malfunctions in the existing denesting units, such as those disclosed in U.S. Pat. No. 3,341,072, U.S. Pat. No. 3,478,924, U.S. Pat. No. 4,328,908, or U.S. Pat. No. 6,099,239. Another drawback associated with high speed grading and packing systems is that the denesting units need to be under constant surveillance of operating personal to ensure a sufficient supply of trays to avoid interruption of the entire system. Such denester units are manually supplied with stacks of nested trays containing between 80 and 120 individual trays, or other appropriate numbers resulting in manageable sizes of stacks, which somewhat limits their capacity. Moreover the possibility of varying the stack height between rather large boundaries has also resulted in malfunction of the denester units or packing systems. This has been a particular problem when adherence between the individual trays becomes too great as a result of accumulated weight in a particularly high stack of trays.
Accordingly it is an object of the present invention to propose a tray stack dispenser and method for dispensing stacks of nested trays to a denester of a packing unit, which increases the presently limited capacity. In a more general sense it is thus an object of the invention to overcome or reduce at least one of the disadvantages of the prior art, such as unforeseen interruptions of production. It is also an object of the present invention to provide alternative solutions which are less cumbersome in assembly and operation and which moreover can be made relatively inexpensively. Alternatively it is an object of the invention to at least provide a useful alternative.